"Not forsaking the assembling of ourselves
It is so important that we are faithful to the Lords house. The writer of Hebrews is telling us how important it is to assemble together to exhort one another. The word exhort means to urge strongly, give advice and to give warnings. We can't be good examples to others when we stay home, much less give advice and warnings. So often when this verse is quoted, the last part is left out. "So much the more, as ye see the day approaching." The Bible is full of prophecies pointing to the soon return of Christ. Therefore the latter part of the verse is telling us that we need to be in church more now than any time in history. Jesus said in Mark 13: 35-37, " Watch ye therefore: for ye know not when the master of the house cometh, at evening, or at midnight, or at the cockcrowing, or in the morning: lest coming suddenly he find you sleeping. and what I say unto you I say unto all, Watch."
Let's not be caught sleeping when our Lord comes back. Paul said in 1st Thessalonians 4:6, "Therefore let us not sleep, as do others: but let us watch and be sober."